The prevalence of depression among medically ill patients is very high, with estimates of 10-36% for inpatients. Depressed medically ill patients have an increased morbidity either through depression-related medical illness complications or through depression itself.
It can be very challenging to diagnose depression in medically ill patients and still adhere strictly to DSM-IV criteria. For example, the diagnosis of major depression requires that any of the symptoms (e.g., insomnia) are not the direct effect of a general medical condition. However, it can be extremely difficult to say that some symptoms are unrelated to a medical condition. ★So what does one do on a consultation service? Easy. Don't follow the DSM-IV diagnoses that closely. Some people have suggested that all symptoms be counted toward depression. This leads to some over-diagnosis, of course, but that is preferable to leaving depression untreated by taking a conservative approach to diagnosis.
Depression can have significant effects on a patient's course of hospitalization. For example, depression is associated with increase lengths of stay and increased treatment costs. Medical illness with comorbid major depressive disorder is associated with poor outcomes. This associate holds ture for cancer, multiple sclerosis, and heart disease. ★Most notably, comorbid depression is associated with an increased mortality rate even when controlling for smoking, physical health, and alcohol abuse.
Depression and coronary artery disease
A significant number of patients with CAD present with depressed mood and up to a quarter of the patients meet criteria for major depressive disorder. Importantly, a very interesting study called the Sertraline Antidepressant Heart Attack Trial (with an ever-curious acronym) assessed the benefits of sertraline after myocardial infarction. There were modest trends towards fewer severe cardiovascular sequelae as well as modest increases in left ventricular ejection fraction.
Depression and cancer
Estimates for the prevalence of major depressive disorder in cancer patients ranges widely from 10-50%, probably because of the heterogeneity of cancer and psychosocial supports. ★Classically, pancreatic cancer is considered to have the strongest association with depression.
Depression and cancer are associated with adverse health events. For example, depression can be a predictor of mortality, decreased compliance with treatment, increased hospital stays, decreased quality of life, and decreased ability to cope with pain.
Depression and neurological disease
Damage to the frontal lobes, hippocampus, thalamus, amygdala, and basal ganglia can be associated with depression.
- Parkinson's disease: Depressive symptoms occur in up to half of all Parkinson's patients. However, the symptoms more commonly meet criteria for dysthymic disorder rather than major depression. There are many possible etiologies and certainly Parkinson's disease itself gives rise to many functional and psychosocial changes to be associated with depression. To complicate matters, however, treatments of Parkinson's, such as levodopa, can also give rise to depression.
Assessing depression in Parkinson's is challenging because many of the disease features (inactivity, masked facies, etc) can be confused with depression. Even so, depressive symptoms are an important and reversible aspect of Parkinson's.
Poststroke depression
About one-fourth of patients experience major depression after a stroke. Although a meta-analysis did not support the contention, it is commonly held that lesions of the left frontal lobe or left basal ganglia are more likely to be associated with depression.
Post-partum depression
From 50-80% of new mothers experience mood swings after giving birth, usually beginning about 3-4 days after delivery. Symptoms such as crying, anxiety, irritability, and insomnia may worsen during the latter part of the first week, but usually resolve by the end of the second week. If symptoms last more than two weeks, then one shoudl be concerned about major depression. The major risk factor (50-60%) for post partum depression is a previous pregnancy-related depression. In addition, the history of major depression, bipolar disorder, poor social support, marital stressors, and ambivalence towards the pregnancy also increase the risk for postpartum depression.
Mild depression can just be observed, as SSRIs are not desirable for use while breast-feeding, more severe depression may necessitate ECT. It is important to aggressively treat postpartum depression is not to reduce the possibility of a diminished mother-infant bond.
Epilepsy
Major depressive disorder is found in 20-50% of patients with recurrent seizures, though this prevalence decreases when seizures are controlled.